AK4182A Datasheet, PDF (8/18 Pages) Asahi Kasei Microsystems – Touch Screen Controller

ASAHI KASEI
ON
XP
VREF
AIN+
ADC
YP
VREF-
AIN-
XN
ON
YN


ON
VREF
ADC
VREF-
AIN+
AIN-
ON
[AK4182A]
XP
YP
XN
YN
a) X-Position Measurement Differential Mode
b) Y-Position Measurement Differential Mode


Figure 2 Ґஔଌఆճ࿏
ҰൠʹλονεΫϦʔϯͷҐஔݕग़͸ɺσΟϑΝϨϯγϟϧϞʔυͷํ͕ɺߴਫ਼౓ʹଌఆ͢Δ͜ͱ͕ՄೳͰ͢ɻଌఆి
ѹ͸ిిݯѹʹൺྫ͠·͕͢ɺγϯάϧΤϯυํࣜͰ͸ɺϑϧεέʔϧ͸ɺిిݯѹͷมಈʹؔ܎ͳ͘಺ଂ͋Δ͍͸֎
෦ج४ిѹݯͷిѹʹݻఆ͞Ε·͢ɻैͬͯɺεΫϦʔϯ্ͷಉ͡ҐஔΛλονͯ͠΋ɺผͷҐஔͱͯ͠ଌఆ͞ΕΔՄ
ೳੑ͕͋Γ·͢ɻ·ͨɺೖྗిѹ͕ϑϧεέʔϧΛ௒͑ͯ͠·͏Մೳੑ͕͋Γ·͢ɻσΟϑΝϨϯγϟϧϞʔυͰ͸ɺ
ͦͷΑ͏ͳ͜ͱ͸ͤ·͖ىΜɻ
ͨͩ͠ɺσΟϑΝϨϯγϟϧϞʔυͰ͸ɺA/D ม׵த΋ɺυϥΠόεΠον͸ ON Ͱ͋ΓɺλονεΫϦʔϯʹిྲྀΛ
ྲྀ͠ଓ͚Δඞཁ͕͋Γ·͢ɻ͜Εʹରͯ͠ɺγϯάϧΤϯυํࣜͰ͸ɺτϥοΩϯά࣌ʢ3tDCLKʣͷΈυϥΠόεΠο
ν͸ ON Ͱɺ͜ͷؒظͷΈλονεΫϦʔϯʹిྲྀ͕ྲྀΕɺA/D ม׵த͸εΠονΛ OFF ʹ͢Δ͜ͱ͕ՄೳͰ͢ʢPD0
bit Λ “0” ʹઃఆͨ͠৔߹ʣɻফඅిྲྀͷ࡟ݮͷ఺Ͱ͸γϯάϧΤϯυํ͕ࣜ༗རͰ͢ɻ͔͠͠Ұൠతʹߴਫ਼౓ʹଌఆՄ
ೳͳσΟϑΝϨϯγϟϧํࣜΛ࢖༻͠·͢ɻ
■ λονεΫϦʔϯͷචѹݕग़
λονεΫϦʔϯͷචѹݕग़͸ɺYP ʹ VREF+ɺXN ʹ VREF-ͷిѹΛҹՃͨ͠ঢ়ଶͰɺXPɺYN ͷిѹΛଌఆ͠ɺ̎
ຕͷγʔτͷ઀৮఍߅Λࢉग़͢Δ͜ͱͰಘΒΕ·͢ɻ
͜Εʹ͸ 2 ͭͷํ๏͕͋Γ·͢ɻ
Ұͭ໨ͷํ๏͸ɺX ࣠ͷγʔτ఍߅ʢRxplateʣͷΈ͕ط஌ͷ৔߹Ͱ͢ɻ͜ͷ৔߹ɺԼࣜͷΑ͏ʹɺ઀৮఍߅͕ط஌ͷγ
ʔτͷ࠲ඪͱɺZ1 ҐஔɺZ2 ҐஔΛٻΊΔ͜ͱͰɺ઀৮఍߅Λࢉग़Ͱ͖·͢ɻ
Rtouch = ʢRxplateʣˎʢXposition/4096ʣ * [ (Z2/Z1) – 1]
ೋͭ໨ͷํ๏͸ɺX ࣠ɺY ࣠ͷ྆ํͷγʔτ఍߅ʢRxplate, Ryplateʣ͕ɺط஌ͷ৔߹Ͱ͢ɻ͜ͷ৔߹ɺԼࣜͷΑ͏ʹɺ
઀৮ͨ͠ X ҐஔɺY ҐஔɺZ1 Ґஔ͔Β઀৮఍߅Λ͢·͖Ͱࢉܭɻ
Rtouch = (Rxplate*Xposition/4096)*[(4096/Z1) – 1] – Ryplate*[1 – (Yposition/4096)]


MS0482-J-01




2007/12